Direct color test employing diisonitrosoacetone



United States Pateritf) ice l 1. Patentedlan. 6,1959.

, 8.5 and should preferably be 8.4. -At lower pH values, 2,867,509 e. g.7 to 8, the color developsthmuch more slovi'lly and never reaches theintensity of e attained at t e preferred values. At higher pH, itdevelops rapidly and D then rapidly fades.

Valentine J. Fischer, Newark, N. J., and Jacob I. Miller, Either theoxime or its salts of the alkali metals or Baltimore, Samuel Sass,Edgewood, and Benjamin amines may be employed. The monosodium salt iswittell, Baltimore, assigllors to the United states particularlydesirable, since it is self-buffering at the of America as representedby the secretary of the Army preferred pH 8.4. The same is true of themonodibutyl- No Drawing Application November 8 1956 10 amine salt. Whenthe oxime itself, or other salts, are Serial No. 621,134 employed, abuffer, e. g. sodium bicarbonate or sodium borate, should be added. 1Claim- The reagents may be used in aqueous solution, incor (Grantedunder Title 35, U. s. Code 1952 sec. 266) Pmted in a Q P impregnated ona Surface e. g. paper or silica gel. 7 The invention described hereinmay be manufactured h foliowing examples illustrate various Phases,

and used by or for the Government of the United States our mventlon'EXAMPLE 1 of America for governmental purposes without the payment to usof any royalty thereon. I Preparation of reagents This invention relatesto a new method and composi- Diisonitrosoacetone (DIA) was prepared bythe gzi g g g i gi vg g g g gg f g ggg g i method of Pechmann andWehsarg, Berichte, 19, 2465 th h H t S p py (1886). It was purified by(1) dissolving in hot ether me yp osp Ono non ae or (2) recrystallizingthree times from water heated 0 to 60- 70 C. The water should not beheated above a 3 70 C. as DIA in water decomposes rapidly above thattemperature. The compound should melt with decomposition at 141143 C.when the material in a capillary CH8 tube is placed'in a bath preheatedto approximately 135 ethyl dimethylphosphoramidocyanidate (GA), C. A0.40 solution in water is used as the reagent.

0 A buffering solution (pH 8.4) was prepared by adding T approximately17 ml. of 0.5 N aqueous sodium hydroxide (CH3)N"TP CN to-500' ml. of 0.1M boric acid. The addition of sodium 02H5 hydroxide was controlled bythe use of a pH meter to pinacolyl methylphosphonofiuoridate (GD), givethe exact desired- O o The monosodium salt of dusomtrosoacetone was em-T ployed as a 0.40% solution in water which should be pre- CHPPF E pareddaily. This reagent was prepared by placing 18 g. of diisonitrosoacetoneand 200 ml. of absolute ethanol in Ha CH3 40 a 500 ml. three-neck roundbottom flask which was equipped with a mercury-sealed stirrer, acondenser, and

and cyclohexyl methylphosphonofluondate a dropping funnel. All openingswere protected from 0 atmospheric moisture by calcium chloride tubes. Ag OHPCHa sodium ethylate solution was prepared by the addition I of 3.6g. of metallic sodium to 100 ml. of absolute alco- Q hol. This was addeddropwise to the stirred reaction CHTC Q mixture of diisonitrosoacetonesolution from the dropoollootively known as the w m We are able to pingfunnel. After addition of the sodium ethylate soludetect extremelyminute quantities of these agents in the tion, the mixture was Stirredfor 15 -i filtered and f f vapors droplots or in solution washed oncewith approximately 25 ml. of. absolute o invention i also applicable tothe detection f 1 ethanol. The sodium salt was dried in avacuumdesicca-' other phosphorus compounds, i i g a um f tor over phosphoruspentoxide. A theoretical yield of a commercial insecticides, and to acidhalides. In general, light Yellow Product Was obtained- The Sodium S wefind that compounds which give the Schoenemann dorkens oonsldorably at Cand decomposes reaction (see abstracts of the Pittsburgh Conference on-Y -1 l v Analytical Chemistry and Applied Spectroscopy, The diandtrisodium salts were prepared by adding ruary 27-March 2, 1956,Analytical Chemistry Group, the appropriate theoretical quantities ofsodium ethylate Pittsburgh Section, A i c i Society), also to give thesesalts. The treatment was similar to that respond to our test. of themonosodium salt. When a capillary tube contain- A particular advantageof our reaction resides in the 3g the dlsodillm s l as P e in a bath at160 C. no

fact that it is especially sensitive to the most toxic com- Ylolemoooomposltlon was observed. However, When pounds, o" the G Agentsinserted in a bath at 170 C. the compound decomposed Our invention isbased on the reaction, under alkaline Vlolently- The i Salt when Placedin a P conditions, f compounds of the above group with lary showed noviolent decomposition in a bath at 133 diisonitroso acetone (acetonedioxime) At the compound decomposed Violently- EXAMPLE 2 E 1T? Procedure0H 0H (a) Calibration curve.-Prepare solutions of GB, or

with the production of a colored compound.

The pH is important. It should lie in the range 8.3 to

other compounds which give the Schoenemann reaction, in 2-propanol. Thedilutions are so selected that #4.) convenient'concenu'ations in therange of 5 to 60 micrograms per ml. can be aliquoted. Pipette 1 ml. ofeach agent concentration into Klett tubes or similar optical tubes andadd 1 ml. of diisonitrosoacetone (or the dior trisodiumdiisonitrosoacetone salt) reagent.(0.40% solution). Mix and add 3 ml. ofbuffer solution (the sodium borate solution described above or 2%aqueous sodium bicarbonate), stir, allow to stand, measure on a Klett-Summersonphotoelectric colorimeter using filter No. 50 (470-530 me), oron a similar instrument. The color remains stable for minutes. Prepare acalibration curve by plotting agent concentration against Kiett units(or the readingsofthe particular colorimeter employed).

When themonosodium or monodibutyl amine salt of diisonitrosoacetone isused as the'reagent, it is unnecessary to employ the buffer solution.Add 1 ml. of the 2'-propanol solution, 3-m1. of'distilled water and 1ml. of the reagent;

When the GB (or other compound) is, to bedeterminedin'aqueous solution,it is possible to increase. the sensitivity of the system by thefollowing procedure. Make up known dilutions of the compound in waterrather than in 2-propanol. Add 4 ml. of the agent solution and 1 ml. ofthe monosodium diisonitrosoacetone reagent. Prepare the calibrationcurve as before.

(b) Sample determination-Pipette samples of GB or other compounds insolution into the Klett tubes and treat as described in the procedurefor the calibration curve. Apply the reading to the previously preparedcalibration curve to obtain the concentration of agent in the unknownsolution.

The sensitivities, i. e. the minimum detectable quart: tities of some ofthe agents in solution using the procedure given above, are shown inTable 1.

Sensitivity,

Micrograms per milliliter of solution Compound N-B nmn nnninamirio GA-GD GF- Diisopropylphosphofluoridate Tetraethylpyrrmh nsnh rite Para-mumBenzenesulfonyl chloride Benzoyl (hlm'idp Bram inc I H WNWWOOIMHHHHHcedures.:

EXAMPLE 3 Crayon A salt mixture, which was prepared by the. reactionof 5equivalents of sodium ethylate with 1 mole of DIA in' ethanolwas-pressed in amoldat- 1000 lb./sq-; in: to-

form a crayon. On subjecting the caryon mark to GB vapor or droplets, amagenta color is formed.

EXAMPLE 4 Impregnated silica g el A salt mixture, which was prepared-bythe reaction of 3, equivalents of sodium methoxide with one mole of.

. Impregnated paper The impregnated paper was prepared by dipping-filterpaper into a strongsolution of the trisodium saltof DIA in methanol andallowing the methanol to evaporate. It was found that a color test couldbe obtained on this paper when moisture with water beforeor-aftercontacting the paper withGB or the other-compoundsof the group.

EXAMPLE 6 Capsule Gelatine capsules are prepared containing 40 mg. eachof the disodium salt of diisonitrosoacetone. A capsule is dropped intoml. of an aqueous solution. Development of a magenta color indicates thepresence of one of the compounds of the group identified above.

We claim:

A method for the detection of a substance selected from the groupconsisting of isopropyl methylphosphonofluoridate, ethyldimethylphosphoroarnidocyanidate, pina colyl methylphosphonofluoridate,cyclohexyl methylphosphonofiuoridate, diisopropylphosphofluoridate,tetraethyl pyrophosphate, para-oxon, and parathion, which comprisesreacting said compound under alkaline conditions with a compoundselected from the group consisting of diisonitrosoacetone'and.the amineand; alkali metal salts;

thereof.

References Cited in the fileof this patent UNITED STATES PATENTS 458,244Tyree Aug. 25, 1891 691,249 Dieterich Jan. 14, 1902v 2,054,8851 ShroterSept. 22, 1936 OTHER REFERENCES Welcher Organic Anal. Reagents Vol.1947, P;

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.2,867,509 January 6, 1959 It is hereby certified that error appears inthe -printed specification I of the above numbered patent requiringcorrection and that the said Letters Patent should read as correctedbelow.

Valentine J. Fischer et al.

Column 3, Table 1-, first column thereof, line 5, for"Diis'opropylphosphofluoridate read Diisopropylphosphorofluoridate sametable,

first column thereof, last line, for "N=-Bromosuccinamide'! readN-Bromosuccinimide column 4, line 41, for "diisopropylphosphofluorifldate" read diisopropylphosphorofluoridate Signed and sealed this 28thday of July 1959.

(SEAL) Attest:

KARL H. AXLINE ROBERT c. WATSON Attesting Oflicer Commissioner ofPatents

